The contribution of propagons and diffusons in heat transport through calcium-silicate-hydrates

Zhou, Yun; Morshedifard, Ali; Lee, Jae-Ho; Qomi, Mohammad Javad Abdolhosseini

doi:10.1063/1.4975159

Cited by 35 publications

(26 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2(c) and 3(d)). This high transport efficiency of diffusons here agrees well with the previously reported high contribution from diffusons to thermal conductivity in amorphous materials [10,49,50]. The study in Fig.…”

Section: Wave-packet Simulationsupporting

confidence: 92%

Strong phase correlation between diffusons governs heat conduction in amorphous silicon

Zhang¹,

Guo²,

Bescond³

et al. 2021

Preprint

View full text Add to dashboard Cite

Understanding the thermal vibrations and thermal transport in amorphous materials is an important but long-standing issue in several theoretical and practical fields. Using direct molecular dynamic simulations, we demonstrate that the strong phase correlation between local and nonpropagating modes, commonly named diffusons in the terminology of amorphous systems, triggers conduction of heat. By considering the predominance of collective excitations in amorphous silicon, the predominant contribution of diffusons, due to phase correlation, is predicted, which further reveals the unique temperature and length dependences of thermal conductivity in amorphous silicon. The explored wavelike behavior of diffusons uncovers the unsolved physical picture of mode correlation in prevailing models and further provides an interpretation of their ability to transport heat. This work introduces a framework for understanding thermal vibrations and thermal transport in amorphous materials, as well as perspectives on the wave nature of thermal vibrations.

show abstract

Section: Wave-packet Simulationsupporting

confidence: 92%

Strong phase correlation between diffusons governs heat conduction in amorphous silicon

Zhang¹,

Guo²,

Bescond³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…For another monoatomic amorphous solid, amorphous carbon, Lv and Henry suggested that propagons can contribute 13% of the total thermal conductivity if 6.5 THz is assumed as the propagon‐to‐diffuson transition frequency . Following Boltzmann transport theory to calculate the thermal conductivity contributed by propagons and Allen–Feldman theory to calculate the diffuson contribution and adopting 2.47 THz as the propagon‐to‐diffuson transition frequency, Zhou et al suggested that in the disordered glue of cement, propagons contribute more than 30% of the total thermal conductivity, and diffusons contribute the remainder …”

Section: Contributions From Different Heat Carriersmentioning

confidence: 99%

“…[55] Following Boltzmann transport theory to calculate the thermal conductivity contributed by propagons and Allen-Feldman theory to calculate the diffuson contribution and adopting 2.47 THz as the propagon-to-diffuson transition frequency, Zhou et al suggested that in the disordered glue of cement, propagons contribute more than 30% of the total thermal conductivity, and diffusons contribute the remainder. [56] Liu et al prepared hydrogenated amorphous silicon film by hot-wire chemical vapor deposition, measured the room temperature thermal conductivity with time domain thermoreflectance (TDTR), and obtained the temperature dependence (80-300 K) of the thermal conductivity with the 3ω method. [57] Their sample had the typical temperature dependence of an amorphous solid and a strong dependence on the MFP of heat carriers.…”

Section: Contributions From Different Heat Carriersmentioning

confidence: 99%

Thermal Conductivity of Amorphous Materials

Zhou

Cheng

Chen

et al. 2019

Adv Funct Materials

195

110

View full text Add to dashboard Cite

Thermal conductivity is one of the most fundamental properties of solid materials. The thermal conductivity of ideal crystal materials has been widely studied over the past hundreds years. On the contrary, for amorphous materials that have valuable applications in flexible electronics, wearable electrics, artificial intelligence chips, thermal protection, advanced detectors, thermoelectrics, and other fields, their thermal properties are relatively rarely reported. Moreover, recent research indicates that the thermal conductivity of amorphous materials is quite different from that of ideal crystal materials. In this article, the authors systematically review the fundamental physical aspects of thermal conductivity in amorphous materials. They discuss the method to distinguish the different heat carriers (propagons, diffusons, and locons) and the relative contribution from them to thermal conductivity. In addition, various influencing factors, such as size, temperature, and interfaces, are addressed, and a series of interesting anomalies are presented. Finally, the authors discuss a number of open problems on thermal conductivity of amorphous materials and a brief summary is provided.

show abstract

“…When mixed with water, cementitious materials produce a glue that binds aggregates to form concrete, the most ubiquitously consumed man‐made material on the face of the earth . The global environmental concerns associated with the concrete's inordinate mass production has reinvigorated a fresh interest in understanding concrete's mechanical, thermal, and durability properties across length scales. Intensive research has been dedicated to understand and manipulate the molecular building block of concrete's glue, known as the calcium‐silicate‐hydrate (C–S–H) .…”

Section: Introductionmentioning

confidence: 99%

Nanolayered attributes of calcium‐silicate‐hydrate gels

et al. 2019

Self Cite

View full text Add to dashboard Cite

Calcium‐silicate‐hydrates (C–S–H) gel, the main binding phase in cementitious materials, has a complex multiscale texture. Despite decades of intensive research, the relation between C–S–H's chemical composition and mesoscale texture remains experimentally limited to probe and theoretically elusive to comprehend. While the nanogranular texture explains a wide range of experimental observations, understanding the fundamental processes that control particles’ size and shape are still obscure. This paper strives to establish a link between the chemistry of C–S–H nanolayers at the molecular level and formation of C–S–H globules at the mesoscale via the potential‐of‐mean‐force (PMF) coarse‐graining approach. We propose a new thermomechanical load‐cycling scheme that effectively packs polydisperse coarse‐grained nanolayers and creates representative C–S–H gel structures at various packing densities. We find that the C–S–H nanolayers percolate at ~10% packing fraction, significantly below the percolation of ideal hard contact oblate particles and rather close to that of overlapping ellipsoids. The agglomeration of C–S–H nanolayers leads to the formation of globular clusters with the effective thickness of ~5 nm, in striking agreement with small angle neutron and X‐ray scattering measurements as well as nanoscale imaging observations. The study of pore structure and local packing distribution in the course of densification shows a transition from a connected pore network to isolated nanoporosity. Furthermore, the calculated mechanical properties are in excellent agreement with statistical nanoindentation experiments, positioning nanolayered morphology as a finer description of C–S–H globule models. Such high‐resolution description becomes indispensable when investigating phenomena that involve internal building blocks of globules such as shrinkage and creep.

show abstract

The contribution of propagons and diffusons in heat transport through calcium-silicate-hydrates

Cited by 35 publications

References 37 publications

Strong phase correlation between diffusons governs heat conduction in amorphous silicon

Strong phase correlation between diffusons governs heat conduction in amorphous silicon

Thermal Conductivity of Amorphous Materials

Nanolayered attributes of calcium‐silicate‐hydrate gels

Contact Info

Product

Resources

About